WILLOW, Alaska — The festivities are over, and the serious competition began Sunday in the 1,100-mile Iditarod Trail Sled Dog Race.

Under sunny skies, the drivers of 71 dog teams took off from frozen Willow Lake to begin the race to the old gold rush town of Nome on Alaska’s western coast. Several thousand fans spread out along the trail to cheer them on.

Lingering was the carnival atmosphere of Saturday’s 11-mile ceremonial start in Alaska’s largest city, Anchorage, 50 miles to the south. But mushers were focused on racing for real with their 16-dog teams on a trail that can see temperatures plunge to 50 below zero.

“Get the heck out of Dodge, just like all the other mushers,” veteran Zack Steer of Sheep Mountain said. “You know, we want to hit the trail.”

Three-time champion Lance Mackey of Fairbanks is seeking his fourth consecutive win, and is among five past Iditarod winners in the race. He stayed busy seeing to last minute preparations Sunday and signed autographs for fans, including some from outside the state here to watch some of the action in person.

“Thanks for coming all this way,” he told them. “Hopefully we won’t disappoint anybody.”

Among the visiting fans was Sharon Camalo of Lafayette, La., who was seeing Alaska for the first time, thrilled to get a taste of the Iditarod.

“I was always interested in it and I thought it was fascinating that they could endure that kind of exposure to the elements,” she said.

Also running this race is Canadian Hans Gatt, who became a four-time winner of the 1,000-mile Yukon Quest International Sled Dog Race in February. Mackey also has won that race four times, and is the only musher to win the back-to-back Quest and Iditarod in the same year — a feat he’s accomplished twice.

For the first time in Iditarod history, mushers will be tested for drugs and alcohol along the trail. Anyone testing positive would face disqualification.

The Iditarod began testing the sled dogs for prohibited substances in 1994.

Mackey, a throat cancer survivor, has been open about using medical marijuana in past Iditarods. He said he is honoring the drug rule, which has existed in some form since 1984 but was never strictly enforced.

In another first, a Jamaican musher is the first Caribbean entry in the Iditarod.

Newton Marshall, a 26-year-old resident of St. Anne Parish, has been training with Mackey this winter. Sponsored by Margaritaville icon Jimmy Buffett, Marshall completed the Yukon Quest last year as a rookie.

“I want to get to that starting line,” he said shortly before setting off to the wild. “Just want to get out there.”

The race is being run with less money this year. Iditarod officials say they lost almost $1 million in funding after video deals collapsed and major sponsors dropped their support. Cushioning the blow somewhat, Exxon Mobil has pledged $250,000 annually in a five-year deal, and the city of Nome donated $50,000 earlier this year.

The total purse is $590,000 — down from a high of $925,000 in 2008 — with $50,000 of this year’s prize money donated by four-time champion Jeff King, who also is competing. The winner’s take is a new Dodge truck and $50,000, compared with $69,000 of past years.